// Set the mesh size
h = 1000.0;

// Build the mesh
Point(1) = {    0,    0,0,h};
Point(2) = {25600,    0,0,h};
Point(3) = {25600,25600,0,h};
Point(4) = {    0,25600,0,h};
Line(1) = {1,2};
Line(2) = {2,3};
Line(3) = {3,4};
Line(4) = {4,1};
Line Loop(5) = {1,2,3,4};
Plane Surface(6) = {5};
Extrude {0,0,6400} {
  Surface{6};
}

// This already defines the global volume
Surface Loop(29) = {27, 6, 15, 19, 23, 28};

